[PATCH v4 2/2] commit: fix stdin conflict between message and hook

["Orgad Shaneh via GitGitGadget" <gitgitgadget@gmail.com>]

From: Orgad Shaneh <orgads@gmail.com>

If git commit is executed with -F - (meaning read the commit message
from stdin), and pre-commit hook is also reading from stdin, the
message itself was consumed by the hook before reaching the point
where it is read for the commit message.

Fix this by detecting this case, and passing this information to
run_commit_hook.

Signed-off-by: Orgad Shaneh <orgads@gmail.com>
---
 builtin/commit.c                                 | 14 +++++++++-----
 builtin/merge.c                                  | 12 ++++++++----
 commit.c                                         |  4 ++--
 commit.h                                         |  3 ++-
 sequencer.c                                      |  6 +++---
 t/t7503-pre-commit-and-pre-merge-commit-hooks.sh |  2 +-
 6 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/builtin/commit.c b/builtin/commit.c
index 505fe60956..074a57937f 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -695,11 +695,14 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	int clean_message_contents = (cleanup_mode != COMMIT_MSG_CLEANUP_NONE);
 	int old_display_comment_prefix;
 	int merge_contains_scissors = 0;
+	int message_from_stdin = logfile && !strcmp(logfile, "-");
+	const unsigned hook_flags = message_from_stdin ? 0 : RUN_HOOK_ALLOW_STDIN;
 
 	/* This checks and barfs if author is badly specified */
 	determine_author_info(author_ident);
 
-	if (!no_verify && run_commit_hook(use_editor, index_file, "pre-commit", NULL))
+	if (!no_verify &&
+	    run_commit_hook(use_editor, index_file, hook_flags, "pre-commit", NULL))
 		return 0;
 
 	if (squash_message) {
@@ -724,7 +727,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	if (have_option_m && !fixup_message) {
 		strbuf_addbuf(&sb, &message);
 		hook_arg1 = "message";
-	} else if (logfile && !strcmp(logfile, "-")) {
+	} else if (message_from_stdin) {
 		if (isatty(0))
 			fprintf(stderr, _("(reading log message from standard input)\n"));
 		if (strbuf_read(&sb, 0, 0) < 0)
@@ -998,7 +1001,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 		return 0;
 	}
 
-	if (run_commit_hook(use_editor, index_file, "prepare-commit-msg",
+	if (run_commit_hook(use_editor, index_file, RUN_HOOK_ALLOW_STDIN, "prepare-commit-msg",
 			    git_path_commit_editmsg(), hook_arg1, hook_arg2, NULL))
 		return 0;
 
@@ -1015,7 +1018,8 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	}
 
 	if (!no_verify &&
-	    run_commit_hook(use_editor, index_file, "commit-msg", git_path_commit_editmsg(), NULL)) {
+	    run_commit_hook(use_editor, index_file, RUN_HOOK_ALLOW_STDIN, "commit-msg",
+			    git_path_commit_editmsg(), NULL)) {
 		return 0;
 	}
 
@@ -1701,7 +1705,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 
 	repo_rerere(the_repository, 0);
 	run_auto_maintenance(quiet);
-	run_commit_hook(use_editor, get_index_file(), "post-commit", NULL);
+	run_commit_hook(use_editor, get_index_file(), RUN_HOOK_ALLOW_STDIN, "post-commit", NULL);
 	if (amend && !no_post_rewrite) {
 		commit_post_rewrite(the_repository, current_head, &oid);
 	}
diff --git a/builtin/merge.c b/builtin/merge.c
index 4c133402a6..550b38cd20 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -822,8 +822,11 @@ static void prepare_to_commit(struct commit_list *remoteheads)
 	struct strbuf msg = STRBUF_INIT;
 	const char *index_file = get_index_file();
 
-	if (!no_verify && run_commit_hook(0 < option_edit, index_file, "pre-merge-commit", NULL))
+	if (!no_verify &&
+	    run_commit_hook(0 < option_edit, index_file, RUN_HOOK_ALLOW_STDIN,
+			    "pre-merge-commit", NULL)) {
 		abort_commit(remoteheads, NULL);
+	}
 	/*
 	 * Re-read the index as pre-merge-commit hook could have updated it,
 	 * and write it out as a tree.  We must do this before we invoke
@@ -850,8 +853,9 @@ static void prepare_to_commit(struct commit_list *remoteheads)
 		append_signoff(&msg, ignore_non_trailer(msg.buf, msg.len), 0);
 	write_merge_heads(remoteheads);
 	write_file_buf(git_path_merge_msg(the_repository), msg.buf, msg.len);
-	if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
-			    git_path_merge_msg(the_repository), "merge", NULL))
+	if (run_commit_hook(0 < option_edit, get_index_file(), RUN_HOOK_ALLOW_STDIN,
+			    "prepare-commit-msg", git_path_merge_msg(the_repository),
+			    "merge", NULL))
 		abort_commit(remoteheads, NULL);
 	if (0 < option_edit) {
 		if (launch_editor(git_path_merge_msg(the_repository), NULL, NULL))
@@ -859,7 +863,7 @@ static void prepare_to_commit(struct commit_list *remoteheads)
 	}
 
 	if (!no_verify && run_commit_hook(0 < option_edit, get_index_file(),
-					  "commit-msg",
+					  RUN_HOOK_ALLOW_STDIN, "commit-msg",
 					  git_path_merge_msg(the_repository), NULL))
 		abort_commit(remoteheads, NULL);
 
diff --git a/commit.c b/commit.c
index 775019ec9d..3f5a50164e 100644
--- a/commit.c
+++ b/commit.c
@@ -1631,7 +1631,7 @@ size_t ignore_non_trailer(const char *buf, size_t len)
 }
 
 int run_commit_hook(int editor_is_used, const char *index_file,
-		    const char *name, ...)
+		    unsigned flags, const char *name, ...)
 {
 	struct strvec hook_env = STRVEC_INIT;
 	va_list args;
@@ -1646,7 +1646,7 @@ int run_commit_hook(int editor_is_used, const char *index_file,
 		strvec_push(&hook_env, "GIT_EDITOR=:");
 
 	va_start(args, name);
-	ret = run_hook_ve(hook_env.v, RUN_HOOK_ALLOW_STDIN, name, args);
+	ret = run_hook_ve(hook_env.v, flags, name, args);
 	va_end(args);
 	strvec_clear(&hook_env);
 
diff --git a/commit.h b/commit.h
index 5467786c7b..72215d57fb 100644
--- a/commit.h
+++ b/commit.h
@@ -352,6 +352,7 @@ int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 int compare_commits_by_gen_then_commit_date(const void *a_, const void *b_, void *unused);
 
 LAST_ARG_MUST_BE_NULL
-int run_commit_hook(int editor_is_used, const char *index_file, const char *name, ...);
+int run_commit_hook(int editor_is_used, const char *index_file, unsigned flags,
+		    const char *name, ...);
 
 #endif /* COMMIT_H */
diff --git a/sequencer.c b/sequencer.c
index 684ea9d5ce..505101c29c 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -1171,8 +1171,8 @@ static int run_prepare_commit_msg_hook(struct repository *r,
 	} else {
 		arg1 = "message";
 	}
-	if (run_commit_hook(0, r->index_file, "prepare-commit-msg", name,
-			    arg1, arg2, NULL))
+	if (run_commit_hook(0, r->index_file, RUN_HOOK_ALLOW_STDIN,
+			    "prepare-commit-msg", name, arg1, arg2, NULL))
 		ret = error(_("'prepare-commit-msg' hook failed"));
 
 	return ret;
@@ -1496,7 +1496,7 @@ static int try_to_commit(struct repository *r,
 		goto out;
 	}
 
-	run_commit_hook(0, r->index_file, "post-commit", NULL);
+	run_commit_hook(0, r->index_file, RUN_HOOK_ALLOW_STDIN, "post-commit", NULL);
 	if (flags & AMEND_MSG)
 		commit_post_rewrite(r, current_head, oid);
 
diff --git a/t/t7503-pre-commit-and-pre-merge-commit-hooks.sh b/t/t7503-pre-commit-and-pre-merge-commit-hooks.sh
index 7bfb7435c6..a243b7efa1 100755
--- a/t/t7503-pre-commit-and-pre-merge-commit-hooks.sh
+++ b/t/t7503-pre-commit-and-pre-merge-commit-hooks.sh
@@ -292,7 +292,7 @@ test_expect_success 'with user input' '
 	test_cmp user_input hook_input
 '
 
-test_expect_failure 'with user input combined with -F -' '
+test_expect_success 'with user input combined with -F -' '
 	test_when_finished "rm -f \"$PRECOMMIT\" user_input hook_input" &&
 	cp "$HOOKDIR/user-input.sample" "$PRECOMMIT" &&
 	echo "user input" >user_input &&
-- 
gitgitgadget